The background description provided here is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure.
An exhaust gas sampling apparatus typically includes a dilution air supply passage that provides dilution air to a dilution air tunnel, and a sampling probe that provides exhaust gas to the dilution air tunnel. The dilution air may be clean, filtered air that is free of oil, such as zero air or nitrogen, and may be compressed air. In the dilution air tunnel, particles in the exhaust gas react with the dilution air, causing the particles to experience condensational growth. This growth of the emissions particles improves the accuracy of emissions analyzers in the exhaust gas sampling systems.
On occasion, an exhaust gas sampling apparatus may develop a leak due to, for example, improper assembly, a defect in a component, or wear. Conventional systems and methods for detecting a leak in an exhaust gas sampling apparatus either pressurize the apparatus or create a vacuum in the apparatus and monitor the pressure in the apparatus. If a change in the pressure is greater than a predetermined amount within a predetermined period, the systems and methods detect a leak in the exhaust gas sampling apparatus. These conventional systems and methods may not detect a leak in an exhaust gas sampling apparatus as accurately and/or as quickly as desired.